Cartridge link manufacture



M y 2, 1944 A. E. BORT ON CARTRIDGE LINK MANUFACTURE INVENTOR.

AL/t YA/ E. fio/er o/v. BY 4mg 91% A 2" Filed Aug. 7, 1942 Patented May 2, 1944 iJNi QFHCE CARTRIDGE LINK MANUFACTURE Application August 7, 1942, Serial No. 454,051

9 Claims.

The invention here disclosed relates to the manufacture of the connecting links for machine gun cartridges.

Prior applications for patents, Ser. No. 419,062 filed Nov. 14, 1941, and Ser. 423,467 filed Dec. 18, 1941, are referred to as illustrating the general principles of such manufacture and details by which the blanks for the links are obtained from the full Width of the strip stock.

To thus utilize the full Width of the strip, the material for the end loops of one blank is taken from the extreme edge portions of the strip and the material for the intermediate hinge loop of the adjoining blank is taken from the mid-portion of the strip in line with and in some instances, actually out of the material between. the material for the first mentioned end loops.

To provide clearance for free hinging action between the links, it has been the practice in shaping the end loops to subject the blanks to a certain amount of stretclrng to space such loops far enough apart to receive between them the intermediate hinge loop of an adjoining link.

This stretching of the material weakens and imposes various stresses and tends to produce variations in size and strength in the links.

Special objects of the present invention are to avoid objections and limitations such as mentioned and to accomplish rapid low cost production of free hinging cartridge links of substantially uniform gage and equal strength.

The novel features of invention by which the foregoing and other desirable objects are attained are set forth in the following specification,

illustrated by way of example in the accompanying drawing and broadly covered in the claims.

In the drawing, a' present preferred embodiment of the invention is illustrated, but it is contemplated that the exact form of the invention may be modified and changed all within the intent and broad scope of the invention as hereinafter defined and claimed.

Fig. l is a broken face view of a strip of stock in process, illustrating the piercing, shearing, trimming, preforming, severing and first bending, operations and showing in particular the long scrap removed in the trimming operation.

Fig. 2 is an edge or plan view of the same.

Fig. 3 is a face view of the completed formed link after the flaring and loop closing operations.

Fig. 4 is a plan View of the completed link and Fig. 5 is an end view of the same.

Fig. 6 is a cross-sectional detail on line 66 Fig. 1.

at the first station to form the spaced openings 7, 8, in the intermediate portion of the strip and sheared at the second station on lines 9, I0, extending inwardly from opposite edges back to said perforations to define the upper and lower, wider and narrower tongues Il, I2, of one blank and the intermediate, hinge loop forming tongue I3, and connected back portion I l, of a preceding blank.

The edge view, Fig. 2, shows how in the shearing operation the intermediate tongue portion I3, is slightly ofiset and forced back out of the general plane of the strip.

At the third station, Fig. 1, the blanks are trimmed to remove a slight excess of material at the ends of the upper and lower tongues and to shape these tongues to their final outlines.

A special feature of the invention is that in effecting such trimming, a long sliver of scrap is taken out between the upper tongue H, of one blank and the intermediate tongue I3, of the preceding blarrk to provide what will be in effect, a permanent fixed extent of clearance between the cartridge encircling loops or one link and the hinge loop of the adjoining link,

The long scrap removed in this trimming operation is shown in Fig. 1 as being an L-shaped piece having a long narrow portion I5, taken off the lower edge of the upper tongue I I, and a connected angularly related part I5, removed from between the end of this tongue and the upper shoulder of the full width back portion I4. Also, as a part of the trimming operation, there is removed a similar but smaller piece of L-shaped long scrap Ii, from between the upper edge of the lower tongue I2, and about the end portion of this tongue and the lower shoulder of the full Width back part I4.

At the trimming station, also, the material at the junction of the upper and lower tongues with the full width back portion I4, is indented as at I8, is, to locate the points of starting the bending of the upper and lower tongues into substantially parallel cartridge encircling loops.

The next operation consists in rounding the intermediate section of the back member at the root of the intermediate tongue therewith to a curvature at 20, corresponding to an arc of the final hinge loop and in curving and outwardly offsetting the edge portions of said back member at 2!, 22, on slightly larger radius arcs to freely overlie the upper and lower cartridge loops of an adjoining link.

This offsetting of the edge portions of the back In Fig. 1, the strip of stock is shown as pierced member efifects a certain amount of foreshortenleft connecting the end of the intermediate hinge loop tongue I3, with the edge of the back portion Hi.

At the final station, the severed and partially preformed blank is first folded about a forming post at 25, to bend back and partially curve the intermediate and end tongues as at the right in Fig. 2, and then the blank is slipped down to a lower level, where the tongues are fully curled inwardly into the circular formation shown in Fig. 4. v

' As a part of the final forming operations, the lower narrower tongue is reduced and flared as indicated at 2?, preferably as disclosed in copending application 419,062, to fit the bullet end of the cartridge.

Where heretofore it has been necessary to stretch the material to spread the pair of loops apart to enable them to receive the hinge loop of an adjoining link between them and where that was accomplished in and as a part of the flaring operation, that now is no longer necessary, or required to a much lesser extent, because of the clearance afforded by the taking out of the long scrap between the tongues of adjoining blanks. The removal of this long scrap also enables the offsetting and consequent foreshortening of the back piece, as much as may be considered desirable. The taking out of the long scrap therefore provides greater leeway in the designing of the link to meet particular requirements and in the designing of the tools to produce such links. The contracting and tapering or flaring as it is termed, has a natural tendency to reduce the overall width of the lower tongue, more or less assuring clearance between the upper edge of that loop and the lower edge of the intermediate loop of an adjoining link,

thus to provide ample clearance at this point more or less equivalent to the clearance provided by the taking out of the long scrap at the upper hinge loop.

The bending of the wide center tongue l3, into loop formation has a tendency, due to the greater stretching of the material, along the edges to bellmcuth the mid-portion of the loop, slightly reducing the diameter in that region between the upper and lower edges of the loop. While this variation from truly cylindrical shape may be hardly perceptible in one link, in the aggregate, it may constitute a very objectionable amount in a whole chain of the links. This bellmouth eifect also constitutes an inherent weakness, since the reduced diameter portion of the loop, under heavy load, may begin to yield and thus initiate a breaking down or stretching of the chain. The reduction in diameter by such bellmouthing also is objectionable as in some instances, interfering with the free hinging of this loop on the cartridge which serves at the time as a hinge pin.

All these objections are avoided in the present invention by imparting a transverse curvature to the mid-portion of the tongue or strap l3, before it is bent into loop formation, substantially as indicated at 28, Figs. 1, 2 and 6. This transverse embossment is ironed out in the rolling and bending of the tongue into loop formation. In such bending, the material flattens out into the substantially cylindrical formation shown in Figs. 3, 4 and 5. The transverse embossment of the mid-portion of the tongue may provide a slight excess of material to compensate for a possibly greater stretching of the metal along the edges, thus in the end to provide the efiect of a truly flat strip rolled into cylindrical form. This flattened strip rolls readily on the hinge pin and takes the load equally across its full width, thus being stronger in efiect because capable of carrying a greater load without showing any signs of weakening.

The transerse curvature may be imposed by cooperating embossing dies operating at the preforming station, as indicated in Fig. 1.

What is claimed is:

1. The method of manufacturing cartridge links, which comprises piercing the intermediate portion of a stock strip, shearing the stock inwardly at points longitudinally removed from said piercing and thence longitudinally to the pierced portions to define adjoining blanks with an intermediate longitudinally extending tongue of one blank between longitudinally extending side tongues of the adjoining blank, then trimming a long scrap of material from between tongues of said adjoining blanks, severing the end blank from the strip and bending the tongues of the same into cartridge embracing loop formation.

2. The method of manufacturing cartridge links, which comprises piercing the intermediate portions to define adjoining blanks with an inwardly at points longitudinally removed from said piercing and thence longitudinally to the pierced portions to define adjoining blanks with an intermediate longitudinally extending tongue of one blank between longitudinally extending side tongues of the adjoining blank, trimming a long scrap of material between tongues of said adjoining blanks, curving and foreshortening the material across the strip connected with said tongues and severing the end blank from the strip and bending the tongues of the same into cartridge embracing loop formation.

3. The method of manufacturing cartridge links, which comprises piercing the intermediate portion of a stock strip, shearing the stock inwardly at points longitudinally removed from said piercing and thence longitudinally to the pierced portions to define adjoining blanks with an intermediate longitudinally extending tongue of one blank between longitudinally extending side tongues of the adjoining blank, trimming a long scrap of material between tongues of said adjoining blanks, curving and oifsetting portions of the material connected with said tongues and separating the blanks and shaping the tongues of the same into cartridge embracing loops.

4. The method of manufacturing cartridge links, which comprises shearing a strip of stock in the outline of a pair of spaced longitudinal tongues connected, to one edge of a transverse back portion and an intermediate tongue extending longitudinally from the opposite edge of said transverse back portion and With the intermediate tongue of one blank between the pair of tongues of an adjoining blank, trimming a long scrap of longitudinally extending material from between the tongues of adjoining blanks and severing the blanks from the strip stock and bending the tongues of the same in cartridge embracing loops.

5. The method of manufacturing cartridge links, which comprises shearing a strip of stock in the outline of a pair of spaced longtiudinal tongues connected to one edge of a transverse back portion and an intermediate tongue extending longitudinally from the opposite edge of said transverse back portion and with the intermediate tongue of one blank between the pair of tongues of an adjoining blank, trimming a long scrap of longitudinally extending material from between the tongues of adjoining blanks, severing the blanks from the strip stock and bending the tongues of the same in cartridge embracing loops by first indenting the pair of tongues at their juncture with said transversely extending back portion, then continuing the indentations and curving said back portion and bending the intermediate tongue to the same curvature.

6. The method of manufacturing cartridge links, which comprises shearing a strip of stock in the outline of a pair of spaced longitudinal tongues connected to one edge of a transverse back portion and an intermediate tongue extending longitudinally from the opposite edge of said transverse back portion and with the intermediate tongue of one blank between the pair of tongues of an adjoining blank, trimming a long scrap of longitudinally extending material from between the tongues of adjoining blanks, severing the blanks from the strip stock and bending the tongues of the same in cartridge embracing loops by first indenting the pair of tongues at their juncture with said transversely extending back portion, then continuing the indentations and curving said back portion and bending the intermediate tongue to the same curvature and offsetting the end sections of said back portion to which the pair of tongues are attached.

7. The method of manufacturing cartridge links from the full width of strip stock, which comprises shearing strip stock inwardly from opposite edges to outline a pair of tongues along the edge of the strip connected to a back portion extending transversely across the strip and an intermediate tongue extending longitudinally from the opposite edge of said back portion and with an intermediate tongue of one blank disposed between the pair of edge tongues of an adjoining blank, trimming a long scrap of material from between adjoining tongues of adjoining blanks, severing the trimmed blanks from the strip stock and bending said blanks into cartridge embracing loop formation.

8. The method of manufacturing cartridge links, which comprises cutting link blanks out of material in a form to provide a tongue for embracing a cartridge, imparting transverse curvature to the mid-part of such tongue forming portion and then rolling said tongue forming portion into the form of a loop and in such rolling operation ironing out the transverse curvature previously imparted thereto.

9. The method of manufacturing cartridge links or the like, which comprises shearing strip stock into spaced longitudinal tongues connected to one edge of a transverse back portion and an intermediate tongue extending longitudinally from the opposite edge of said transverse back portion and with the intermediate tongue of one blank between said pair of side tongues of an adjoining blank, trimming a long scrap of longitudinally extending material from between the intermedaite tongue of one blank and. the opposed side tongue of an adjoining blank to provide clearance between such tongues, bending the tongues into circular formation and flaring the inner edge of the other of said side tongues to provide clearance between the same and the opposing edge of an intermediate tongue.

ALWYN E. BORTON. 

